Weapons?

Weapons!

It turns out if you want to blow up an asteroid coming your way, or at least nudge it off its course, lobbing some megatons of TNTs in its general direction is a lot harder than sending over some nukes.

Also, things put on top of nukes when they blow up go really high, really fast, even if they're heavy. So if you add a nuke chute to the back of your spaceship, and some mechanism for dampening the blow you can build some really awesome interplanetary transports. With enough nukes you can even go to other stars in more or less reasonable time frames!

The only realistic plan to go to the stars and return within, say, 40 years without using techno-magic is to use lasers [1]. Nukes just cannot do that at all, they are only good for efficient travel within solar system.

[1] - https://www.academia.edu/1884741/Roundtrip_interstellar_trav...

The Project Orion people had extensive calculations on how to send a city-sized ship to another star on a ~100 years trip with nukes.

It is laser propulsion that is techno-magic. Even today. I won't register on whatever site to read yet another article on that, but I do bet neither the lasers nor the sail on this one could be made today.

Project Orion was believed to work with technology from the fifties too. That makes me confident that we could build one today, if we wanted to.

What happened to the plan to use a laser to push it of course?

How would we get the nuke to the asteroid? With what rocket? We’d have to detect it early, design and build a massive new gen of rockets, and then essentially hit a target moving at cosmic velocities far enough away that we don’t turn a rifle into a shotgun.

Realistically all we can do at this time to cope with an extinction level impact, is crying and dying.

You'd presumably get the nukes to the asteroid with conventional chemical rockets, although I suppose some sort of Project Orion propulsion system is not out of the question. That's what you'd want to do once you got there; you'd basically be counting on nuclear weapons as an incredibly energy-dense form of rocket fuel.

There's nothing that comes close to the MJ/kg of a modern thermonuclear weapon.

Sadly we have nothing that comes close to getting a fleet of nuclear warheads far enough to intercept before it’s too close and we shotgun ourselves. Most likely forms of diversion involve years of planning and deployment, and that’s minus the hasty R&D we’d need to do.

For some discussion of the specifics...

https://space.stackexchange.com/questions/7960/could-we-deal...

Nobody said it's easy. But the last fifty years or so are the first time period were the chances of a successful defense are bigger than zero. We have top men working on it: https://en.wikipedia.org/wiki/Asteroid_impact_avoidance

Right now it isn’t easy or hard, it’s impossible. We probably have the tech, but it would need to be ready to launch on detection. Worse, we have shit detection.

So yes, in theory we could divert some impactors, but in practice right now? No. Nukes don’t help either.

We could blow up a couple of nukes in space and watch for radio echos to find asteroids... Well, except that nukes in space are illegal.

Turning a rifle into a shotgun on this case is a good thing, and may completely solve the problem.

But, anyway, unless we wait way too much, it's better to deflect an asteroid than to break it.

>> How would we get the nuke to the asteroid?

Oh, it's simple- we'd sent in Bruce Willis [1].

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[1] https://en.wikipedia.org/wiki/Armageddon_(1998_film)